The difference is twofold. If a method is marked synchronized, the thread entering must acquire the object lock before it can enter the method and begin work. As a statement, the synchronized requires the thread to acquire the object lock before it can go any further in the method.
It is also possible (but not generally advisable) for the synchronized statement to name an object lock other than the 'this' object lock.
The different in the statements you've written is pretty small, since the the synchronized statement is the first instruction inside the method. In this case, however, it is possible for an arbitrary number of threads to enter these methods and then contend for the object lock.
Make visible what, without you, might perhaps never have been seen. - Robert Bresson